Compositions useful in golf balls

ABSTRACT

Curable polyurethane, polyurea and polyurethane/polyurea compositions that are particularly useful as the outer layer and/or at least one inner layer of golf balls, cured compositions, golf balls comprising the cured composition, and methods of increasing the initial velocity of a golf ball using the curable polyurethane, polyurea and polyurethane/poly urea compositions are disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 12/514,538 filed Feb. 3, 2010, now issued as U.S. Pat. No.8,324,336, which is the National Stage of International Application No.PCT/US2008/065080 filed May 29, 2008, which claims the benefit of U.S.Application No. 60/940,546 filed May 29, 2007, the entire disclosures ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates generally to curable polyurethane, polyurea andpolyurethane/polyurea hybrid compositions that are particularly usefulas the outer layer and/or at least one inner layer of golf balls, to thecured compositions, to golf balls comprising the cured composition, andto methods of increasing the initial velocity of a golf ball using thecurable polyurethane, polyurea and polyurethane/polyurea hybridcompositions.

BACKGROUND OF THE INVENTION

Golf ball compositions are formed from a variety of materials, includingbalata and ionomer resins. Balata is a natural or synthetictrans-polyisoprene rubber. Balata covered balls are favored by the morehighly skilled golfers because the softness of the cover allows theplayer to achieve higher spin rates sufficient to more precisely controlball direction and distance, particularly on shorter shots.

However, balata covered balls are easily damaged, and thus lack thedurability required by the average golfer. Accordingly, alternativecover compositions have been developed in an attempt to provide ballswith spin rates and a feel approaching those of balata covered balls,while also providing a golf ball with a higher durability and overalldistance.

Ionomer resins have, to a large extent, replaced balata as a cover stockmaterial. Chemically, ionomer resins are a copolymer of an olefin and analpha, beta ethylenically-unsaturated carboxylic acid having 10-90% ofthe carboxylic acid groups neutralized by a metal ion. See U.S. Pat. No.3,264,272. Commercially available ionomer resins include, for example,copolymers of ethylene and methacrylic or acrylic acid neutralized withmetal salts. These are sold by E.I. DuPont de Nemours and Co. under thetrademark “SURLYN®” and by the Exxon Corporation under the trademark“ESCOR®” and the trademark “IOTEK®.” These ionomer resins aredistinguished by the type of metal ion, the amount of acid, and thedegree of neutralization.

U.S. Pat. Nos. 3,454,280, 3,819,768, 4,323,247, 4,526,375, 4,884,814,and 4,911,451 all relate to the use of SURLYN®-type compositions in golfball covers. However, while SURLYN® covered golf balls as described inthe preceding patents possess virtually cutproof covers, they haveinferior spin and feel properties as compared to balata covered balls.

Polyurethanes and polyureas have also been recognized as usefulmaterials for golf ball covers since as early as about 1960. Forexample, U.S. Pat. No. 3,147,324 is directed to a method of making agolf ball having a polyurethane cover, which is durable whilemaintaining the “feel” of a balata ball. The polyurethane covers can beformed from polyurethane prepolymers cured with curing agents having atleast one active hydrogen groups (such as amines and/or polyols),wherein the prepolymers are formed from the reaction of polyols withpolyisocyanates.

There are other examples of the use of polyurethane and polyurea as golfball cover materials. For example, U.S. Pat. No. 4,123,061 disclosesthat a golf ball can be made from a polyurethane prepolymer of polyetherand a curing agent, such as a trifunctional polyol, a tetrafunctionalpolyol, or a diamine. U.S. Pat. No. 5,334,673 discloses the use ofthermoset and thermoplastic polyurethanes for forming golf ball covers,and in particular, thermoset polyurethane covered golf balls made from acomposition of polyurethane prepolymer and a slow-reacting amine curingagent and/or a difunctional glycol. U.S. Pat. No. 5,484,870 disclosesthat golf ball covers may be prepared from polyurea compositions thatare prepared by combining an organic isocyanate having at least twoisocyanate functional groups with an organic amine curing agent.

Polyurethane is a product of a reaction between a polyurethaneprepolymer and a polyol curing agent. The polyurethane prepolymer is aproduct formed by a reaction between a polyol and a diisocyanate. Thecuring agent is either a polyamine or a polyol. It has been discoveredthat a polyurethane prepolymer cured with a slow-reacting curing agentselected from the group of slow reacting polyamine curing agents orpolyfunctional glycols produces a golf ball cover that has gooddurability and performance. These golf balls have been found to haveimproved shear resistance and cut resistance compared to golf ballshaving covers made from either balata or soft SURLYN® material.

The first commercially successful polyurethane covered golf ball wasTitleist's PROFESSIONAL™ golf ball in 1993. The principal reason for thedelay in bringing polyurethane composition golf ball covers on themarket was that it was a daunting engineering task to apply a coveringof polyurethane composition to a golf ball core to form a golf ballcover having a uniform thickness. Further progress has been made in thearea of polyurethane balls, including improved water resistance, UVlight stability, abrasion resistance and durability.

There has been further progress in the uses of polyurethane andpolyurea, including the use of polyurea/polyurethane hybrids. Accordingto the Polyurea Development Association, a polyurea is defined as theresult of a chemical reaction between an isocyanate and an amine.Polyurethane is defined as the result of a chemical reaction between anisocyanate and a polyol. Polyurea/polyurethane hybrid formulations aredefined as the result of a chemical reaction between an isocyanate and amixture of polyol and polyamine reactants. These formulations generallyprovide an “intermediate” polyurea that displays many of the sameproperties of a polyurea. The isocyanate can be aromatic or aliphatic innature and can be monomer, polymer, or any variant reaction ofisocyanates, quasi-prepolymer or a prepolymer. The prepolymer orquasi-prepolymer can be made of an amine-terminated polymer resin or ahydroxyl-terminated polymer resin.

Further improvements to golf ball performance is desired in suchcharacteristics as initial velocity of the golf ball. Initial velocityis related to the coefficient of restitution of a golf ball. Theinteraction between the club head and the golf ball determines thedistance and direction the golf ball will travel. The relationshipbetween the speed of the club head and the initial velocity of the golfball depends on the coefficient of restitution of the golf ball, whichvaries between different types of balls. The distance that the golf balltravels is dependent on the speed of the club head and the initialvelocity of the golf ball, which varies between different types ofballs. When the golf ball is struck by the club, it is deformed andflattened by the force of impact. A golf ball with a harder core willdeform less than a softer golf ball. In general, a harder ball willtravel further than a softer ball because it deforms less and willefficiently transfer more energy from club to ball. During the impactbetween the golf ball and club head, kinetic energy is transferred andstored as the ball tries to regain its original shape. To obtain maximumdistance in the drive, a golf ball must be selected that maximizesrestitution for the club speed. Further details may be found at:ffden-2.phys.uafedu/211_fall2002.web.dir/josh_fritts/index.html.

Despite these efforts, there is still a need for golf balls with animproved initial velocity without negatively impacting the otherdesirable properties of golf balls. The present invention is directed tothese, as well as other, important needs.

SUMMARY OF THE INVENTION

The invention is generally directed to curable polyurethane, polyureaand polyurethane/polyurea hybrid compositions that are particularlyuseful as the outer layer and/or at least one inner layer of golf balls,to the cured compositions, to golf balls comprising the curedcomposition, and to methods of increasing the initial velocity of a golfball using the curable polyurethane, polyurea and polyurethane/polyureahybrid compositions.

In one embodiment, the invention is directed to compositions,comprising:

-   a. a prepolymer comprising the reaction product of:    -   i. a polyisocyanate; and    -   ii. a component selected from the group comprising a first        polyol, a first polyamine having a molecular weight of greater        than about 900 g/mol or a combination thereof;-   b. a first curing agent which is an optionally substituted    4,4′-methylenebisaniline; and-   c. at least one second curing agent;    wherein said second curing agent has a cure rate that is slower than    the cure rate of said first curing agent.

In one embodiment, the invention is directed to compositions,comprising:

-   a. a polyurethane prepolymer comprising the reaction product of:    -   i. toluene diisocyanate; and    -   ii. polytetramethylene ether glycol.-   b. 4,4′-methylenebis(2-ethylaniline); and-   c. at least one second curing agent selected from the group    consisting of dimethylthio-2,4-toluenediamine;    dimethylthio-2,6-toluenediamine; polycaprolactone triol;    polytetramethyleneoxide-di-p-aminobenzoate; polyetheramine; dimer    diol; and mixtures thereof.

In other embodiments, the invention is directed to the curedcompositions described above, wherein the composition comprises formingat least one layer in a golf ball. In certain preferred embodiments,comprising the cured compositions described herein, the layer forms theouter covering of the golf ball.

In yet other embodiments, the invention is directed to golf balls,comprising:

-   a. a core; and-   b. at least one cured layer described above, either as an outer    layer, at least one inner layer, or both.

In further embodiments, the invention is directed to methods ofincreasing the initial velocity of a golf ball, comprising the steps of

preparing the composition described;

providing a core; and

forming at least one cured layer on said core from said composition.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to curable polyurethane,polyurea and polyurethane/polyurea hybrid compositions that areparticularly useful as the outer layer and/or at least one inner layerof golf balls, to the cured composition, to golf balls comprising thecured composition, and to methods of increasing the initial velocity ofa golf ball using the curable polyurethane, polyurea andpolyurethane/polyurea hybrid compositions. The novel polyurethane,polyurea and polyurethane/polyurea hybrid polymer provide manybeneficial properties, many of which overcome shortcomings of the priorart.

As used herein, the term “polyurea” refers to a polymer that is theresult of a chemical reaction between an isocyanate and an amine.

As used herein, the term “polyurethane” refers to a polymer that is theresult of a chemical reaction between an isocyanate and a polyol.

As used herein, the phrase “polyurea/polyurethane hybrid formulation”refers to a polymeric mixture that is the result of a chemical reactionbetween an isocyanate and a mixture of polyol and amine reactants.

As used herein, the term “polymer” refers to, but is not limited to,oligomers, adducts, homopolymers, random copolymers, pseudo-copolymers,statistical copolymers, alternating copolymers, periodic copolymer,block copolymers, bipolymers, terpolymers, quaterpolymers, other formsof copolymers, substituted derivatives thereof, and mixtures thereof.These polymers can be linear, branched, block, graft, monodisperse,polydisperse, regular, irregular, tactic, isotactic, syndiotactic,stereoregular, atactic, stereoblock, single-strand, double-strand, star,comb, dendritic, and/or ionomeric.

As used herein, the term “prepolymer” refers to a polymer of relativelylow molecular weight, usually intermediate between that of the monomerand the final polymer or resin, which may be mixed with compoundingadditives, and which is capable of being hardened by furtherpolymerization during or after a forming process.

As used herein, the term “polyol” refers to any aliphatic or aromaticcompound containing at least two free hydroxyl groups. In practicing theprocesses disclosed herein, the selection of a suitable polyol is simplya matter of choice. For example, suitable polyols may have a backbonechain selected from the following classes: saturated or unsaturated,linear or branched or cyclic (including heterocyclic), aliphatic oraromatic (including mononuclear or polynuclear aromatics).

As used herein, the term “polyamine” refers to any aliphatic or aromaticcompound containing at least two amine groups. In practicing theprocesses disclosed herein, the selection of a suitable amine is simplya matter of choice. For example, suitable polyamines may have a backbonechain selected from the following classes: saturated or unsaturated,linear or branched or cyclic (including heterocyclic), aliphatic oraromatic (including mononuclear or polynuclear aromatics).

As used herein, the term “optionally substituted4,4′-methylenebisaniline” refers to any compound containing the4,4′-methylenebisaniline moiety:

-   -   The 4,4′-methylenebisaniline backbone

wherein each R², R³, R⁵, R⁶, R^(2′), R^(3′), R^(5′), R^(6′) can be H,alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocycloalkyl,halogenated alkyl, halogenated alkenyl, halogenated alkynyl, halogenatedcycloalkyl, halogenated heterocycloalkyl, alkoxy, sulfoxy, amino,monosubstituted amine, disubstituted amine, trisubstituted amine,hydroxy, nitro, F, Cl, Br, I, in any combination and further where anyof the hydrogen groups on amino groups or methylene group may besubstituted with another functional group that forms a stable compound.These substituents may be electron withdrawing or electron donating.These substituents may be linear, branched, cyclic, aliphatic oraromatic. The substituents may contain one or more heteroatoms or maycontain no heteroatoms. Examples of optionally-substituted4,4′-methylenebisanilines include 4,4′-methylenebis(2-ethylaniline);4,4′-methylenebis(2-chloroaniline);4,4′-methylene-bis(3-chloro-2,6-diethylaniline);4,4′-methylenebis(2,6-diisopropylaniline);4,4′-methylenebis(3-chloro-2,6-diisopropylaniline);4,4′-methylenebis(2-isopropylaniline);4,4′-methylenebis(2,6-diethylaniline); or a mixture thereof.

As used herein, the term “cure” as used in connection with acomposition, e.g., “a curable material,” “a cured composition,” shallmean that any crosslinkable components of the composition are at leastpartially crosslinked. In certain examples of the present disclosure,the crosslink density of the crosslinkable components, i.e., the degreeof crosslinking, can range from about 5% to about 100% of completecrosslinking. In other examples, the crosslink density can range fromabout 35% to about 85% of full crosslinking. In other examples, thecrosslink density can range from about 50% to about 85% of fullcrosslinking. One skilled in the art will understand that the presenceand degree of crosslinking, i.e., the crosslink density, can bedetermined by a variety of methods, such as dynamic mechanical thermalanalysis (DMTA) in accordance with ASTM E1640-99.

As used herein, the term “cure rate” refers to the amount of time aparticular mixture of prepolymer and curing agents take to react andform the final product.

As used herein, the term “slower reacting curing agent” refers to acuring agent that reacts slower under comparable conditions with respectto an optionally substituted 4,4′-methylenebisaniline. The term refersto a curing agent with nucleophilic groups that are sterically and/orelectronically hindered because of the presence of electron withdrawinggroups or interfering bulky groups situated adjacent to the reactionsites. A long chain flexible spacer of at least four carbons betweenreaction sites or three carbons with electron withdrawing groups alsocontributes to the slower reactivity of curing agents.

As used herein, the term “pot life” refers to the length of time apolymer mixture retains a viscosity low enough for it to be suitable forprocessing.

As used herein, the term “percent NCO” or “% NCO” refers to the percentby weight of free, reactive, and unreacted isocyanate functional groupsin an isocyanate-functional molecule or material. The total formulaweight of all the NCO groups in the molecule or material, divided by itstotal molecular weight, and multiplied by 100, equals the percent NCO.

As used herein, the term “initial velocity” refers to the US GolfAssociation standard. The standard reads, “The initial velocity isdefined as the speed of the ball as it travels 2π feet after impact withthe striker. The measurement is made by electronically timing the ballas it passes through a light source and ballistic screen separated by afixed distance of about 6.283 feet. The light source is locatedapproximately 8.75 inches from the point of impact.

As used herein, the term “coefficient of restitution” or “COR” for golfballs is defined as the ratio of a ball's rebound velocity to itsinitial incoming velocity when the ball is fired out of an air cannoninto a rigid vertical plate. The faster a golf ball rebounds, the higherthe COR it has, the more the total energy it retains when struck with aclub, and the longer the ball flies. The initial velocity is about 50ft/s to about 200 ft/s, and is usually understood to be 125 ft/s, unlessotherwise specified. A golf ball may have different COR values atdifferent initial velocities.

As used herein, the term “golf ball” includes but is not limited to thedefinitions and restrictions set by the U.S. Golf Association and TheRoyal and Ancient Golf Club of St. Andrews, which are incorporatedherein by reference.

As used herein, the term “dispersant” refers to an additive thatincreases the stability of a suspension of powders or pigments in aliquid medium.

As used herein, the subscript letters such as m, n, x, y, and z usedherein within the generic structures are understood by one of ordinaryskill in the art as the degree of polymerization (i.e., the number ofconsecutively repeating units). In the case of molecularly uniformedproducts, these numbers are commonly integers, if not zero. In the caseof molecularly non-uniformed products, these numbers are averagednumbers not limited to integers, if not zero, and are understood to bethe average degree of polymerization.

Any numeric references to amounts, unless otherwise specified, are “byweight.” As used herein, the term “equivalent weight” is a calculatedvalue based on the relative amounts of the various ingredients used inmaking the specified material and is based on the solids of thespecified material. The relative amounts are those that result in thetheoretical weight in grams of the material, like a polymer, producedfrom the ingredients and give a theoretical number of the particularfunctional group that is present in the resulting polymer. Thecompositions of the present disclosure typically comprise a reactionproduct of a polyisocyanate and one or more reactants. In one example,the reaction product can be a polyurethane formed from a polyurethaneprepolymer and a curing agent, the polyurethane prepolymer being areaction product of a polyol and an isocyanate.

As used herein, the term “equivalent” is defined as the number of molesof a functional group in a given quantity of material, and calculatedfrom material weight divided by equivalent weight, the later of whichrefers to molecular weight per functional group.

As used herein, the term “saturated” or “substantially saturated” meansthat the compound or material of interest is fully saturated (i.e.,contains no double bonds, triple bonds, or aromatic ring structures), orthat the extent of unsaturation is negligible, e.g. as shown by abromine number in accordance with ASTM E234-98 of less than about 10,preferably less than about 5.

As used herein, the term “material hardness” refers to indentationhardness of non-metallic materials in the form of a flat slab or buttonas measured with a durometer. The durometer has a spring-loaded indentorthat applies an indentation load to the slab, thus sensing its hardness.The material hardness can indirectly reflect upon other materialproperties, such as tensile modulus, resilience, plasticity, compressionresistance, and elasticity. Standard tests for material hardness includeASTM D2240-02b. Unless otherwise specified, material hardness reportedherein is in Shore D. Material hardness is distinct from the hardness ofa golf ball portion as measured directly on the golf ball (or otherspherical surface). The difference in value is primarily due to theconstruction, size, thickness, and material composition of the golf ballcomponents (i.e., center, core and/or layers) that underlie the portionof interest. One of ordinary skill in the art would understand that thematerial hardness and the hardness as measured on the ball are notcorrelated or convertible.

As used herein, the term “compression,” also known as “ATTI compression”or “PGA compression,” refers to points derived from a Compression Tester(ATTI Engineering Company, Union City, N.J.), a scale well known in theart for determining relative compression of a spherical object.Compression is a property of a material as measured on a golf ballconstruction (i.e., on-ball property), not a property of the materialper se.

As used herein, the term “dimer diol,” refers to a diol species with 36carbon atoms and a molecular weight of about 450 g/mol. Higher molecularweight dimerate polyester polyols (1700 to 3000 g/mol) that are used aspolyols in prepolymer compositions are polymerized from the dimer diol.

As used herein, the term “light stabilizer,” refers to any compound thatabsorbs, alters or reflects any wavelength of the electromagneticspectrum, especially in the visible and ultra-violet ranges, such thatthe properties of a polymer composition are improved, preserved orremain unaltered.

Accordingly, in one embodiment, the invention is directed tocompositions, comprising:

-   a. a prepolymer comprising the reaction product of:    -   i. a polyisocyanate; and    -   ii. a component selected from the group comprising a first        polyol, a first polyamine having a molecular weight of greater        than about 900 grams/mol or combination thereof;-   b. a first curing agent which is an optionally substituted    4,4′-methylenebisaniline; and-   c. at least one second curing agent;    wherein said second curing agent has a cure rate that is slower than    the cure rate of said first curing agent.

In certain preferred embodiments of the compositions described herein, apolyurethane prepolymer is present in a ratio to the total weight of thefirst and second curing agents from about 0.8:1.0 to about 28:1,preferably in about 1:1 to about 10:1, more preferably, about 2:1 toabout 8:1.

In certain preferred embodiments of the compositions described herein,the optionally substituted 4,4′-methylenebisaniline is present in anamount from about 5% by equivalent weight to about 95% by equivalentweight, preferably from about 10% by equivalent weight to about 90% byequivalent weight, more preferably from about 35% by equivalent weightto about 85% by equivalent weight, and even more preferably from about40% to about 80%, based on the total equivalent weight of said firstcuring agent and said second curing agent.

In certain preferred embodiments of the compositions described herein, asecond curing agent is present in an amount from about 5% by equivalentweight to about 95% by equivalent weight, preferably from about 10% byequivalent weight to about 90% by equivalent weight, more preferablyfrom about 35% by equivalent weight to about 85% by equivalent weight,and even more preferably about 40% by equivalent weight to about 80% byequivalent weight, based on the total equivalent weight of said firstcuring agent and said second curing agent.

In certain preferred embodiments of the compositions described herein,the prepolymer is a polyurethane ionomer, polyurea ionomer,polyurethane, polyurea, polyurethane/polyurea hybrid,polyurethane/polyurea ionomer or a mixture thereof.

In certain preferred embodiments of the compositions described herein,the polyisocyanate is 1,6-hexamethylene-diisocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane;3,3′-dimethyldiphenyl-4,4′-diisocyanate; 4,4′-dicyclohexylmethanediisocyanate; 4,4′-diphenylmethane diisocyanate; carbodiimide-modifieddiphenylmethane diisocyanate; cyclohexane-1,3-diisocyanate;cyclohexane-1,4-diisocyanate; cyclohexyl diisocyanate; dimer of1,6-hexamethylene diisocyanate; dodecane-1,12-diisocyanate; isophoronediisocyanate; meta-tetramethylxylene diisocyanate; methyl cyclohexylenediisocyanate; naphthalene diisocyanate; para-phenylene diisocyanate;para-tetramethylxylene diisocyanate; polymeric 4,4′-diphenylmethanediisocyanate; tetramethylene-1,4-diisocyanate; toluene diisocyanate;triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate; triisocyanateof 2,4,4-trimethyl-1,6-hexane diisocyanate; trimer of 1,6-hexamethylenediisocyanate; trimethyl-hexamethylene diisocyanate, xylene diisocyanate;2,4′-diphenylmethane diisocyanate; 2,2′-diphenylmethane diisocyanate;diphenylmethane diisocyanate; or a mixture thereof.

In certain preferred embodiments of the compositions described herein,the first polyol is 1,4-butanediol initiated polycaprolactone;1,5-pentanediol initiated polycaprolactone; 1,6-hexanediol initiatedpolycaprolactone; acrylic polyol; C36 dimerate polyester polyol,diethylene glycol initiated polycaprolactone; hydroxy-terminated liquidisoprene rubber; neopentyl glycol initiated polycaprolactone;hydroxy-terminated polyesters of dimethylol proprionic acid;hydroxy-terminated polyesters of isopthalic sulfonic acid;ortho-phthalate-1,6-hexanediol polyester polyol; hydroxy-terminatedpolyesters of dimerized fatty acids, poly(ethylene oxide cappedoxypropylene) glycol; poly(hexamethylene adipate) glycol;poly(hexamethylene carbonate) glycol; poly(oxypropylene) glycol;poly(phthalate carbonate) glycol; polybutadiene glycol; polybutyleneadipate glycol; polycarbonate glycols containing bisphenol A; polyesterpolyol, polyethylene adipate glycol; polyethylene propylene adipateglycol; polyethylene terephthalate polyester polyol; polycaprolactonepolyol; polytetramethylene ether glycol initiated polycaprolactone,polytetramethylene ether glycol; propylene glycol initiatedpolycaprolactone; trimethylol propane initiated polycaprolactone; or amixture thereof.

In certain preferred embodiments of the compositions described herein,the first polyamine is polytetramethylene ether diamine;polyoxypropylene diamine; amine-terminated polycaprolactone;amine-terminated C36 dimerate polyesters; amine-terminated polyesters ofdimerized fatty acid; amine-terminated polyesters of dimethylolproprionic acid; amine-terminated polyesters of isophthalic sulfonicacid; or a mixture thereof.

In certain preferred embodiments of the compositions described herein,the second curing agent is a second polyamine or a second polyol. Incertain preferred embodiments of the compositions described herein, thesecond curing agent is 1,2-bis-(sec-butylamino)benzene;1,3-[bis-(2-hydroxyethoxy)]-diethoxybenzene;1,3-bis-(2-hydroxyethoxy)benzene;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene;1,4-bis-(sec-butylamino)benzene; 1,4-butanediol;1,4-cyclohexyldimethylol; 2-methyl-1,4-butanediol;3-methyl-1,4-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol;2-methylpentamethylene-diamine; 2-propanol-1,1′-phenylaminobis;3,5-diethyltoluene-2,4-diamine; 3,5-diethyltoluene-2,6-diamine;3,5-dimethylthio-2,4-toluenediamine;3,5-dimethylthio-2,6-toluenediamine;4,4′-bis-(sec-butylamino)-diphenylmethane; 4,4′-dibutyl diamine diphenylmethane, 4,4′-methylenebis(2-chloroaniline);4,4′-methylenebis(2-ethylaniline);4,4′-methylenebis(2-isopropylaniline);4,4′-methylene-bis-(3-chloro-2,6-diethyl aniline);4,4′-methylene-bis-(3-chloro-2,6-diisopropylaniline);4,4′-methylenebis(2,6-diethyl aniline);4,4′-methylenebis(2,6-diisopropylaniline); an isomer or mixture ofcyclohexyldimethylol; diethylamino propylamine; diethylene glycol;diisopropanolamine; dimer diol, dimethylamino propylamine;dimethylthio-2,4-toluenediamine; dimethylthio-2,6-toluenediamine;dipropylene glycol; ethylene glycol;hydroquinone-di(beta-hydroxyethyl)ether and its derivatives;imido-bis-propylamine; isomer or mixture of cyclohexanebis(methylamine); isomer or mixture of diaminocyclohexane;N,N′-dialkyldiamino diphenyl methane; polycaprolactone triol;polyetheramine; polyethylene glycol; polypropylene glycol;polytetramethylene ether glycol;polytetramethyleneoxide-di-p-aminobenzoate; propylene diamine; propyleneglycol; resorcinol-di(beta-hydroxyethyl)ether and its derivatives;tetra-(2-hydroxypropyl)-ethylenediamine; tetrahydroxypropylene ethylenediamine; triethanolamine; triisopropanolamine;trimethyleneglycol-di-p-aminobenzoate; trimethylolpropane;diethyltoluenediamine; dimethylthiotoluenediamine; or a mixture thereof.

In certain preferred embodiments of the compositions described herein,the second curing agent is dimethylthio-2,4-toluenediamine,dimethylthio-2,6-toluenediamine, or a mixture thereof. In otherpreferred embodiments, the second curing agent ispolytetramethyleneoxide-di(p-aminobenzoate). In yet other preferredembodiments, the second curing agent is polycaprolactone triol. In otherpreferred embodiments, the second curing agent istrimethyleneglycol-di-(p-aminobenzoate), a polyetheramine, or a mixturethereof. In certain preferred embodiments, the second curing agent is apolyetheramine.

In certain preferred embodiments of the compositions described herein,the optionally substituted 4,4′-methylenebisaniline is4,4′-methylenebis(2-ethylaniline); 4,4′-methylenebis(2-chloroaniline);4,4′-methylenebis(2,6-diethylaniline);4,4′-methylenebis(3-chloro-2,6-diethylaniline);4,4′-methylenebis(2,6-diisopropylaniline);4,4′-methylenebis(2-isopropylaniline);4,4′-methylenebis(3-chloro-2,6-diisopropylaniline); or a mixturethereof.

In certain preferred embodiments of the compositions described herein,the polyurethane prepolymer comprises the reaction product of toluenediisocyanate, polytetramethylene ether glycol,4,4′-methylenebis(2-ethylaniline), and a second slower reaction curingagent.

In certain preferred embodiments of the compositions described herein,the composition further comprises at least one dispersant.

In certain preferred embodiments of the compositions described herein,the composition further comprises at least one coloring composition. Incertain preferred embodiments, the coloring composition comprises awhite pigment. In certain preferred embodiments, the white pigment istitanium dioxide, zinc oxide, or a mixture thereof. In certain preferredembodiments, the coloring composition further comprisespolyoxypropylenediamine. In certain preferred embodiments, the coloringcomposition comprises a colorant.

In certain preferred embodiments of the compositions described herein,the composition further comprises at least one light stabilizer. Incertain preferred embodiments of the compositions described herein, thelight stabilizer is triazine, benzoxazinone, benzotriazole,benzophenone, benzoate, formamidine, cinnamate, propenoate, aromaticpropanedione, benzimidazole, cycloaliphatic ketone, formanilide,oxamide, cyanoacrylate, benzopyranone, salicylate, succinate, sebacate,or a mixture thereof. Without wishing to be bound by any particulartheory, it is believed that these compounds absorb harmful UV light andrapidly convert the light into harmless energy, such that the compoundsreduce or prevent the rapid degradation of color in many conventionalgolf balls covers.

In another embodiment, the invention is directed to compositions,comprising:

-   a. a polyurethane prepolymer comprising the reaction product of:    -   i. toluene diisocyanate; and    -   ii. polytetramethylene ether glycol.-   b. 4,4′-methylenebis(2-ethylaniline); and-   c. at least one second curing agent selected from the group    consisting of dimethylthio-2,4-toluenediamine;    dimethylthio-2,6-toluenediamine; polycaprolactone triol;    polytetramethyleneoxide-di-p-aminobenzoate; polyetheramine; dimer    diol; and mixtures thereof.

In yet other embodiments, the invention is directed to a golf ball,comprising:

-   a. a core; and-   b. at least one layer

In certain preferred embodiments, at least one layer of the golf ballcomprises the composition of the invention. In other preferredembodiments, at least one layer comprising the composition of theinvention forms the outer covering of the golf ball.

In other embodiments, the invention is directed to methods of increasingthe initial velocity of a golf ball, comprising the steps of:

preparing the compositions described above;

providing a core; and

forming at least one cured layer on the core from the composition.

The present invention contemplates a polyurethane/polyurea polymericcomposition used in the manufacture of a golf ball comprising thereaction product of at least one polyurethane prepolymer with anoptionally substituted 4,4′-methylenebisaniline as a first curing agentand at least one slower second curing agent. The polyurethane prepolymeris formed from the reaction of at least one polyol with at least onepolyisocyanate. A preferred embodiment of the polyurethane prepolymersynthesis step of this invention is the combination ofpolytetramethylene ether glycol with toluene diisocyanate. However, itcan be contemplated that the polyurethane prepolymer synthesis step ofthis invention could employ a wide range of polyols and polyisocyanates.

The polyurethane/polyurea polymers suitable for use in the invention area product of a reaction between at least one polyurethane prepolymerwith an optionally substituted 4,4′-methylenebisaniline and at least oneslower curing agent. An embodiment of this invention contemplates theuse of an optionally substituted 4,4′-methylenebisaniline with at leastone slower curing agent in the reaction mixture with at least onepolyurethane prepolymer. The preferred embodiment of this invention isto use the combination of an optionally substituted4,4′-methylenebisaniline with a polyamine or a polyol as the curingagents.

A slow reacting curing agent with respect to an optionally substituted4,4′-methylenebisaniline means that the nucleophilic groups on the slowreacting curing agent are sterically and/or electronically hinderedbecause of the presence of electron withdrawing groups or interferingbulky groups situated adjacent to the reaction sites. A long chainflexible spacer of at least four carbons between reaction sites or threecarbons with electron withdrawing groups also contributes to the slowerreactivity of curing agents.

The rate of curing for a polyurethane, polyurea andpolyurethane/polyurea hybrid mixture can be measured, for example, by aVibrating Needle Curemeter (VNC) that is manufactured by RapraTechnology Limited. It is achieved by suspending a steel needle in thecuring formulation. The needle is vibrated vertically by a smallelectrodynamic vibrator driven by a signal generator. Resistance to itsmovement is ultimately recorded as the voltage output.

Slow reacting polyamine curing agents such as3,5-dimethylthio-2,4-toluenediamine and3,5-dimethylthio-2,6-toluenediamine are isomers with two or more of thesites on the benzene ring substituted with groups that sterically hinderthe reaction ability of the amine groups. Slow reacting polyamine curingagents such as trimethylene glycol-di-p-aminobenzoate andpolytetramethyleneoxide-di-p-aminobenzoate have the two amine groupssituated adjacent to two electron withdrawing carbonyl groups and areseparated by flexible spacers, trimethylene, andpolytetramethyleneoxide, respectively. Still another suitable group ofpolyamines comprises N,N′-dialkyldiamino diphenyl methane such as4,4′-dibutyl diamine diphenyl methane wherein the aromatic amine group,is substituted by an alkyl group to become an aromatic secondary amine.The alkyl groups attached to the amine atoms, the flexible spacersbetween the amine groups, electron withdrawing groups and bulky groupssubstituted adjacent to the amine atoms all contribute to attenuate thereactivity of the amine, offering an increase in reaction time.

Preferably, the polyurethane polymers of the present invention comprisefrom about 1% to about 100% of the cover composition and/or theintermediate layer composition. In other preferred embodiments, thepolyurethane polymers of the present invention comprise from about 10%to about 95% of the cover composition and/or the intermediate layercomposition. In other preferred embodiments, the polyurethane polymersof the present invention comprise from about 25% to about 90% of thecover composition and/or the intermediate layer composition. In certainpreferred embodiments, the intermediate layer composition comprises oneor more other polymers and/or other materials as described below. Suchother polymers include, but are not limited to polyurethane/polyureaionomers, polyurethane/polyurea hybrids, polyurethanes, polyureas, epoxyresins and mixtures thereof. Unless otherwise stated herein, allpercentages are given in percent by weight of the total composition ofthe golf ball layer in question.

Other suitable materials which may be combined with the polyurethane,polyurea and polyurethane/polyurea hybrid polymers in forming the coverand/or intermediate layer(s) of the golf balls of the invention includeionic or non-ionic polyurethanes or polyureas, siloxanes, epoxy resinsand mixtures thereof. For example, the cover and/or intermediate layermay be formed from a blend of at least one polyurethane polymer withanionic and cationic urethanes/polyurethanes, urethane epoxies,polyureas and ionic polyureas and mixtures thereof. Examples of suitableurethane ionomers are disclosed in U.S. Pat. No. 5,692,974, thedisclosure of which is hereby incorporated by reference in its entirety.Other examples of suitable polyurethanes are described in U.S. Pat. No.5,334,673. Examples of appropriate polyureas are discussed in U.S. Pat.No. 5,484,870 and examples of suitable polyurethanes cured with epoxygroup containing curing agents are disclosed in U.S. Pat. No. 5,908,358.These are all incorporated herein by reference.

Other conventional ingredients, e.g., density-controlling fillers,ceramics and glass spheres are well known to the person of ordinaryskill in the art and may be included in cover and intermediate layerblends of the present invention in amounts effective to achieve theirknown purpose.

The present invention can be used in forming golf balls of any desiredsize. The USGA dictates that the size of a competition golf ball must belarger than 1.680 inches in diameter. Golf balls of any size can be usedfor leisure golf play. The preferred diameter of the golf balls is fromabout 1.680 inches to about 1.800 inches. The more preferred diameter isfrom about 1.680 inches to about 1.760 inches. A diameter of from about1.680 inches to about 1.740 inches is most preferred, however diametersanywhere in the range of from 1.70 to about 1.95 inches can be used.Oversize golf balls with diameters above about 1.760 inches to as big as2.75 inches are also within the scope of the present invention.

The coefficient of restitution (CoR) is the ratio of the relativevelocity between two objects after direct impact to the relativevelocity before impact. As a result, the CoR can vary from 0 to 1, with1 being equivalent to a perfectly or completely elastic collision and 0being equivalent to a perfectly plastic or completely inelasticcollision. Since a ball's CoR directly influences the ball's initialvelocity after club collision and travel distance, manufacturers areinterested in this characteristic for designing and testing golf balls.

According to a technical report provided by the U.S. Golf Association,experiments have shown that the coefficient of restitution of impactbetween a golf ball and a club head is a smoothly declining (nearlylinear) function of club head speed (Chou, P. C., Liang, D., Yang, J,Gobush, W. (1994), “Contact Forces, Coefficient of Restitution, and SpinRate of Golf Ball Impact”, Science and Golf II, E & F N Spon) (Cochoran,A. J. (1998), “Development and Use of One-Dimensional Models of a GolfBall”, Science and Golf III, Routledge) (Lemons, L. D. (1998),“Experiments in Golf Ball-Barrier Impacts”, Science and Golf III,Routledge). This is understood to be a function of the hysteretic,rate-dependent nature of the polymeric materials used in golf ballconstruction (Tavares, G., Sullivan, M., and Nesbitt, D., (1998) “Use ofFinite Element Analysis in Design of Multilayer Golf Balls,” Science andGolf III, Human Kinetics) (Quintavalla, S. J. (2004), Finite ElementModel of the Impact Behavior of a Golf Ball. USGA Test Center ReportRB/mat2004-01) (Quintavalla, S. J. and Johnson, (2004) S. H., Extensionof the Bergstrom-Boyce Model to High Strain Rates, Rubber Chem. andTech., 77 (5)). After impact, the trajectory of the golf ball isgoverned by well-understood aerodynamic forces as well as gravity.Launch conditions for the test were obtained by striking balls using aservo-controlled mechanical golfer, equipped with a USGA conformancedriver (Aeson, 9°), as per the USGA Overall Distance Standard.Experimental Determination of the Effects of Clubhead Speed on DriverLaunch Conditions on the Effects of Drive Distance for Balls Used by thePGA Tour. USGA Technical Report RB/cor2006-01. Steven J. Quintavalla,Ph.D. USGA Research Engineer, Apr. 19, 2006.

One conventional technique for measuring CoR uses a golf ball or golfball subassembly, air cannon, and a stationary vertical steel plate. Thesteel plate provides an impact surface weighing about 100 pounds orabout 45 kilograms. A pair of ballistic light screens, which measureball velocity, are spaced apart and located between the air cannon andthe steel plate. The ball is fired from the air cannon toward the steelplate over a range of test velocities from 50 ft/sec to 180 ft/sec. Asthe ball travels toward the steel plate, it activates each light screenso that the time at each light screen is measured. This provides anincoming time period proportional to the ball's incoming velocity. Theball impacts the steel plate and rebounds through the light screens,which again measure the time period required to transit between thelight screens. This provides an outgoing transit time periodproportional to the ball's outgoing velocity. The coefficient ofrestitution can be calculated by the ratio of the outgoing transit timeperiod to the incoming transit time period.

A CoR measuring method employed by the U.S.G.A. uses a golf ball or golfball subassembly, a launching device, and a substantially fixed titaniumdisk. The titanium disk intending to simulate a golf club is circular,and has a diameter of about 4 inches, and has a mass of about 200 grams.The disk is mounted on an X-Y-Z table so that its position can beadjusted relative to the launching device prior to testing. A pair ofballistic light screens are spaced apart and located between thelaunching device and the titanium disk. The ball is fired from thelaunching device toward the titanium disk at a predetermined testvelocity. As the ball travels toward the titanium disk, it activateseach light screen so that the time period to transit between the lightscreens is measured.

This provides an incoming transit time period proportional to the ball'sincoming velocity. The ball impacts the titanium disk, and reboundsthrough the light screens which measure the time period to transitbetween the light screens. This provides an outgoing transit time periodproportional to the ball's out going velocity. The CoR can be calculatedusing the mass of the ball, the mass of the disk, outgoing timedifference and incoming time difference.

EXAMPLES

The present invention is further defined in the following Examples, inwhich all parts and percentages are by weight and degrees are Celsius,unless otherwise stated. It should be understood that these examples,while indicating preferred embodiments of the invention, are given byway of illustration only. From the above discussion and these examples,one skilled in the art can ascertain the essential characteristics ofthis invention, and without departing from the spirit and scope thereof,can make various changes and modifications of the invention to adapt itto various usages and conditions.

Example 1

Two polyurethane/polyurea compositions were formulated as shown below inTables 1 and 2. Both trials provided balls with an unexpectedly highinitial velocity or coefficient of restitution.

TABLE 1 Weight % of curing Chemicals/Formulations (grams) Equivalentscomposition Polyurethane Prepolymer 693.57 g 1 eq. Prepolymer to (6.07%NCO) Curing Agent Ratio 4.79:1 Curing Agents

60.33 g 0.475 eq. 41.69%

50.83 g 0.475 eq. 35.13% White Dispersion Rebus 60201 25.15 g 17.38% UVAbsorber 6.29 g  4.35% Hindered amine light stabilizer (HALS) 2.10 g 1.45% Ball Initial Velocity (ft/sec) Foremost Urethane 234.9 CallawayHX Tour 234.8 Titleist Pro VI 232.1 Taylor Made TP/Black 235.6 WilsonStaff Tx4 234.6The initial velocity of the golf balls is the initial velocity of theball as measured after the ball is struck with a Driver club having a 9degree launch angle and the club head having a velocity of about 160ft/s. The coefficient of restitution is a measurement of perfectresilience. A perfectly unresilient composition would have a coefficientof restitution of 0. A perfectly resilient composition would have acoefficient of restitution of 1.

TABLE 2 Weight % of curing Chemicals/Formulations (grams) Equivalentscomposition Polyurethane Prepolymer 693.57 g 1 eq. Prepolymer to (6.07%NCO) Curing Agent Ratio 3.84:1 Curing Agents

88.90 g 0.70 eq. 49.22%

56.75 g 0.25 eq. 31.42% White Dispersion Rebus 60258 26.23 g 14.52% UVAbsorber 6.56 g  3.63% HALS 2.19 g  1.21% Ball Coefficient ofRestitution Foremost Urethane 0.753 Wilson Staff Tx4 0.749

When ranges are used herein for physical properties, such as molecularweight, or chemical properties, such as chemical formulae, allcombinations and subcombinations of ranges specific embodiments thereinare intended to be included.

The disclosures of each patent, patent application and publication citedor described in this document are hereby incorporated herein byreference, in its entirety.

Those skilled in the art will appreciate that numerous changes andmodifications can be made to the preferred embodiments of the inventionand that such changes and modifications can be made without departingfrom the spirit of the invention. It is, therefore, intended that theappended claims cover all such equivalent variations as fall within thetrue spirit and scope of the invention.

What is claimed is:
 1. A composition, comprising: a. a prepolymercomprising the reaction product of: i. toluene diisocyanate; and ii. C36dimerate polyester polyol; b. a first curing agent which is an4,4′-methylenebis(2-ethylaniline); and c. at least one second curingagent selected from the group consisting ofdimethylthio-2,4-toluenediamine; dimethylthio-2,6-toluenediamine;polycaprolactone triol; polytetramethyleneoxide-di-p-aminobenzoate;polyetheramine; dimer diol; and mixtures thereof; wherein said4,4′-methylenebis(2-ethylaniline) is present at a level of about 40-80%equivalent weight, based on the total equivalent weight of said4,4′-methylenebis(2-ethylaniline) and said second curing agent.
 2. Alayer, comprising the cured composition of claim
 1. 3. A golf ball,comprising: a. a core; and b. at least one layer of claim
 2. 4. The golfball of claim 3, wherein said layer forms the outer cover of said golfball.